In general, a variety of medical procedures are known in which invasive procedures are not conducted on body passages such as an esophagus (gullet) that are under or in stricture due to lesion. One of the medical procedures uses a stent made of a superelastic shape memory alloy.
Here, the medical procedure using the stent is performed by inserting the stent, in which wires made of a superelastic shape memory alloy are woven into a hollow cylindrical body having a predetermined length, into a body passage that is under or in stricture due to lesion, with a volume thereof minimized, and distending the body passage that is under or in stricture due to lesion in a radial outward direction until the volume of the stent (or a diameter of a body passage or organ) is restored to its original state.
This medical procedure using the stent requires a separate insertion instrument to insert the stent into the body passage that is under or in stricture.
In this case, the stent insertion instrument for inserting the stent is configured to insert a movable tube from the outside into an outer tube connected to an instrument body to be gripped so as to be able to move the movable tube at a trailing end of the outer tube in a forward/backward direction. Here, a leading end of the movable tube is configured to push the stent that is inserted and mounted into a leading end of the outer tube with a volume thereof reduced.
This stent insertion instrument inserts the stent, which is inserted and mounted into the leading end of the outer tube with the volume thereof reduced, into a body passage such as a blood vessel that is under or in stricture due to lesion.
Here, when the stent is inserted into the body passage that is under or in stricture due to lesion, the insertion is observed by an endoscope inserted separately.
In this way, after the stent reaches the point of stricture, the stent is pushed out of the leading end of the outer tube by an action of pushing the movable tube. While the stent is pushed out of the outer tube from the leading end thereof and is distended and restored to its original shape, the stent is installed so as to push the body passage that is under or in stricture in the radial outward direction.
However, such a conventional stent insertion instrument is not convenient, because the movable tube should be operated in the instrument body using a hand in such a way that it is pushed or pulled in a forward/backward direction in order to be accurately inserted into the targeted organ or body passage that is under or in stricture due to lesion.
Further, the conventional stent insertion instrument is configured so that a surgical position is adjusted by the pushing or pulling operation, and thus has a problem in that it is difficult to accurately select the surgical position, and that fatigue may affect the hand due to the repeated operation.
For this reason, a catheter that can accurately adjust the surgical position by easily converting rotation into reciprocation without the pushing or purling operation and reduce the occurrence of fatigue is urgently required.